Last month, Ma Ailun, a 23-year-old woman from China's northern Xinjiang region, was reportedly electrocuted when she answered a call on her iPhone 5 while it was charging, according to the China-based Xinhua news agency.

The speculation at the time was that Ma Ailun was using a third party charger, for an iPhone her family said she had purchased last December. The authorities are still investigating the incident, and Apple is participating in the investigation.

Apple said not all third party adapters are potentially dangerous but that they were launching the trade-in to allow customers to acquire what it considers are properly designed adapters.

Those wanting an Apple-designed adapter can buy one for $10 (£6.70) in the US or for the approximate equivalent amount in local currencies. To qualify, Apple users must turn in at least one USB power adapter to Apple stores or authorised dealers, and also take along their iPhone, iPad or iPod to enable serial number validations.

US Apple adapters usually cost $19 (£12.70). The offer is limited to one adapter for every Apple gadget shown and adapter taken along to Apple outlets.

The deal will start on 18 August and run through until 18 October. Apple is also inviting the public to take along any other USB adapters they are concerned about, not covered by the offer, so that Apple outlets can dispose of them in an environmentally-friendly manner.